Active magnetic bearings have great potential for improving the efficiency of rotating machinery by: reducing or eliminating the complexity of bearing lubrication systems; enabling high rotational speeds; and providing active means of controlling vibrations in complex rotating masses. Recent advances in power electronics and control microprocessors have made active magnetic bearing systems feasible in, for example, gas turbine engine applications.
Presently, however, active magnetic bearings are unsuitable for high-reliability applications, such as aircraft engine rotor support and vibration control. A major problem is lack of accuracy and reliability of air gap position sensors used for determining rotor shaft position. Hence, it is desirable to provide a method for determining rotor gap position in an active magnetic bearing system, without requiring separate air gap position sensors.